US2255779A - Pile flocking - Google Patents

Description

Patented Sept. 1 6, 1941 PILE FLOCKING Raymond W. Kent, Newton Highlands, Mass.

No Drawing.

Application July 13, 1938,

Serial No. 218,971

34 Claims. (01. 91-70) This invention relates to the manufacture of pile fabrics in which the pile is adhesively attached to a backing, and has particularly to do with the provision of novel methods whereby novel long pile products are produced such as artificial furs and plushes. Though the invention is especially useful in the manufacture of adhesively attached long pile fabrics in which the pile may be as long as an inch, it also finds use in the manufacture of improved and superior shorter pile fabrics such as suedes, etc., in which the shorter pile in any desired quantity may be very firmly attached to a backing.

Heretofore, the process of making imitation suede and the like commonly has involved the application to a cemented rubber-fabric backing, of short fibres of an inch or shorter (usually cotton fiock). The prior methods involve the application to a rubber coated packing of a fluid rubber cement (rubber dissolved in a solvent plus curing materials), the solvent being usually a petroleum base, such as gasoline, together with higher boiling solvents such as kerosene, xylene and the like. These higher boiling solvents are necessary to prevent the too rapid evaporation of the principal solvent which, due to its rapid evaporation, tendsto permit the rubber cement to skim over, thus losing much of its tackiness-the essential characteristic of the cement necessary to facilitate the receiving and initial attaching of the fibres to the backing. During and after the sifted deposit of the fibres, the fabric is subjected to rapid beating as well known in the art in an effort to make the fibres stand erect and to embed the lower ends of the fibres in the rubber cement coating while still tacky and before it hardens due to the evaporation of the solvent. The timing of the movement of the fabric through the machine in the process and the hardening of the unstable rubber cement have to be very carefully correlated in order that an acceptable product may be produced, and, due to the many variables including time, temperature, humidity, etc., frequent failures with resulting losses of a substantial percentage of fabric run through have been the rule rather than the exception. Moreover, the industry to date, despite a long existing demand, has been unable successfully commercially to apply to a backing very long fibres (for example one quarter inch or longer), nor to anchor them firmly, and they tend to mat unevenly and, ball up in the process. Various other disadvantages in the present day commercial processes including the fire and explosion hazard may be avoided by the hereinafter disclosed methods of making the improved prod,-

v ucts of this invention. The present invention is characterized by the novelty of the fabric and excellence of the bonding of the product thereof and, in the method aspects of the invention, by its simplicity and freedom from the disadvantages of the prior processes.

Though it is not essential for the successful practice of the process of this invention, particularly where only short fibres are applied, for best results it is desirable to subject the pile or fibres to a preliminary sizing treatment and thus temporarily render the fibres heavier, smoother and stiffer, for it has been discovered that fibres, especially the longer fibres, when rendered relatively stiff, straight and smooth, can be flocked, and applied as individual sized units, each unit being either a group of threads, or an individual thread comprising a group of fibres, to a backing much more effectively. The sizing may conveniently be done before the pile material is cut, for example, when the pile is in thread form. Ordinarily a water-soluble size is employed, for

example, gelatin, glue, dextrin, gum-tragacanth,

etc., for with warm water such substances may be easily washed out from the finished product after the curing process. If, however, it is desired to render individual fibres permanently stiff, a water-insoluble size may be employed, for example, silicate of soda or resins, natural or synthetic. In either case, the fibres are preferably well dried before being applied to the fabric in order that the units may be separated and each unit applied to the backing in generally endwise arrangement so that the ends thereof become embedded in the' novel bonding agent hereinafter described.

Various sorts of natural and artificial fibres may be used in the practice and products of this invention; Animal fibre, including silk, wool,

' mohair, seal and rabbit fur have been successfully processed as well as various vegetable and artificial fibres usually employed in making thread and textiles, and strips of cut Cellophane, which act as fibres. In the absence of sizing, rayon or hair function much-better than cotton or wool unless the cotton or wool be out very short, but the sizing treatment is a great aid in the utilization of longer cotton and wool fibres.

Rayon fibre is particularly well adapted for use in accordance with this invention, though in the longer lengths, one inch and longer, it is helpful to size the same.

a solution or dispersion, for a period of time far in excess of that required for manipulation thereof during fibre application operations, and until such time as a definite setting or curing step is performed: for example, by a liquid, non-drying, viscous composition consisting essentially of rubber, natural or synthetic (by the latter meaning of the chloroprene type), reactable either with or without reactive agents, such as curing materials, and with or without heat, into a pliable, nonrigid, resilient condition giving fiexible and noncreasing characteristics in the final product.

By the application of the fibre to such an adhesive, the fibres may be most firmly attached to a suitable flexible backing, for example a woven or felt material, and adhere thereto without any tendency of the adhesive to skim over during deposit or beating-of the fibres, and long 30 continuous beating, as long as may be practicably desirable, to receive and embed all the fibre that can be brought into contact with the same, may be utilized,' since the adhesive remains in a non-drying, fluid, viscous and tack-y condition which is stable during the entire beating process, and thereafter, while the intermediate product is in the roll (if rolled), prior to the step of setting up the adhesive. The very act of rolling tends to embed the fibres more firmly in the stiff liquid bonding agent. It is further found that any balling up or gummy massing of fibres (even of long fibres) is avoided, and the product is remarkably free from defects and spots, due to indiscriminate massing and attachment of the fibres to the backing.

Such a normally liquid adhesive, stable in the above sense, may be, and, preferably is,

prepared from practically any type of unvul canized natural rubber. In view of the fact that cheaper grades of rubber are reduced to a fluid condition more readily by heat, and when eventually vulcanized, afford results which compare favorably with the higher and more expensive grades of rubber, it is possible to efiect ma- 55 teriai economy by using the'cheaper grades. Rubberwhich may or may not have been previously milled is placed in. a suitable heater and subjected to a sufiicient temperature for a suficient length of time. to heat-treat it and thereby reduce it to a viscous mass. The exact time of heatingand temperature of treatment 'may be varied considerably and these variables are dependent to an extent one upon the other. They are also dependent to some extent upon the thickness of the mass and the type of rubv ber 'under treatment. These factors may be so chosen. by the operator as to obtain the desired consistency of the bonding agent. In most instances, it will be desirable to heat the product at a temperature and for a time sufficient to bring it to the consistency of honey. For example, the rubber may be placed in a suitable heater (an electrically heated furnace), and subjected to a temperature from 350 F. upwards,

(the maximum temperature employed being limited to temperature below the flash point of the products of decomposition, for example, 600- F. or higher) for from fifteen minutes to four hours,

at which time it will have been reduced to ahoney-like consistency. As an example, rubber sheets one-quarter inch thick have been reduced to the consistency of honey when treated at a temperature of 550 F. for twenty minutes. As

an example of the use of lower temperatures, it has been found that if a temperature of 350 F.

to 400 F. is employed, a product of the consistency described will be obtained if the heating is carried out for a period of two and onehalf to four hours. These examples illustrate the statement that the results obtained in the treatment are direct functions of the time and temperature at which the process is carried out. The temperature may remain substantially conm stant throughout the process, for example, at 550 F., or the heating may be started at a lower temperature, say 200 F. and increased gradually or by steps until the desired hightemperature is reached. Pressure may be employed within the heating chamber if desired to expedite the process, for example, steam pressure may be used varying anywhere from just above atmospheric pressure upwards, for example, up to 150 pounds or more per square inch. The exact time and temperature of treatment to be employed in any given case is readily determinable by the operator who should carry out the heating step until the heat treated rubber has reached the desired honey-like consistency.

Though the heating as described results in chemical, as well as the all important physical changes set forth, the chemical reactions that take place due to the heat-treatment are somewhat obscure and no attempt is here made to explain such reactions resulting in the formation of the non-hardening heat-treated rubber.

' It appears quite definitely that the heat-treated rubber is chemically different from ordinary rubber for it has a materially higher acetone extract value, a different odor, and various other,

dition to a substance similar in its physical characteristics to curedrubber. It is further found that the usual curing materials may be employed, that is, sulphur, accelerators, zinc oxide,- stearic acid, etc. By utilizing accelerators of the ultra type, a cure can be effected at ordinary room temperatures without the necessity of applying an artificial vulcanizing heat. A typical and preferred formula for a complete fibre-to-base bonding agent which has been found successful in practice is as follows (all parts by weight) 1 Parts To this formula there may be added coloring material, as desired, in order to make the color of the bonding medium match or more nearly ap-.

-chloroprene.

- of the embedding operation.

the shorter pile.

proach that of the pile to be applied. Such a heat-treated rubber bonding agent may be employed without the use of any solvents or added resins or the like, though the invention is not limited in its use to the entire absence of any such solvents, etc. A further advantage of the heat-treated rubber bonding agent of this invention is that it readily wets the fibres (even sized fibres) and forms a stronger and firmer bond therewith. Also, when cured, it is substantially odorless and in that respect materially different from the ordinary rubber mixture heretofore employed in the manufacture of pile fabrics.

A similar bonding agent having desirable qualities very similar to the heat-treated rubber just described may comprise a partially polymerized generally as Neoprene," cannot be suitably used in practicing-my process, for its degree of polymerization'is such that it is not in the necessary liquid viscous state, previously described, and, so far as I know, cannot be prepared for liquid coating operations without the use of large amounts of solvents, reducing the adhesive to a relatively non-viscous condition, not suitable for my purposes.

However, I have found that qualities requisite in a bonding agent for practice of my process, are inherent in a chloroprene product not polymerized to the degree present in Neoprene. When made stable by inclusion of polymerizetion retarding ingredients, such a partially polymerized chloroprene may be utilized, with or without plasticizers, as rosin, in accordance with my invention for application of fibres at normal room temperatures and with addition of little or no solvent, according to the particular degree of polymerization thereof. Such a chloroprene compound may also be set to a pliable non-rigid form by a heat treatment after the completion While no effort will be made to describe the precise chemical action involved in the setting up treatment, the reaction will be termed a polymerization and, in any event, produces a resulting resilient bond very similar to that produced by the vulcaniza- Commercial chloroprene, knownv between such long pile fibres with a shorter pile, for example, one-half inch or so. A further modification of the process which may be advantageously employed in the application of very long fibres is in a preliminary deposit of a rela-' tively small amount of very short fibres a; of an inch or less in length, which, it has been discovered, prevents any possibility of the long fibres from lying horizontal on the bonding agent or becoming attached by the bonding agent at other than the ends of said fibres. Following such sparse or light preliminary deposit of very short fibres, the long fibres are then deposited with or without the later application of somewhat shorter fibres as just described. The fabric may then be rolled up, simply laid out fiat, or carried continuously to an oven if one be employed.

It is not essential to the practice of the process that the base have a coat of rubber, calendered or otherwise, applied thereto, for a coating of the bonding agent may be applied directly to one side thereof and the fibres at once deposited. Since the bonding agents of the invention are good wetting agents, a firm bond to the fabric results, as well as the firm bond to the fibres, as above described. i

After the vulcanizing step, the soluble size, if employed, may be washed out by warm water with or without soap. If desired, the product can also be dyed after removing the size but before drying. Then, after drying, beating and blowing, the pile may be completely opened up and the exposed ends may be singed or sheared oil to an even height or left in a shaggy finish. In some cases, successive wettings and dryings may be found desirable.

This application is a continuation in part of my prior copending application, Ser. No. 190, filed January 2, 1935. isHaving described my invention, what I claim 1. The steps in the process of manufacturing a pile surfaced material which consist in applying a naturally liquid adhesive bonding agent having the viscous non-drying gummy characteristics of heat-treated rubber, and reactable tion or curing of the previously described heat .005 of an inch thick. Such coated fabric is then supplied with a coating of the tacky bonding agent of'the type described comprising heattreated rubber plus the curing materials, or a suitable chloroprene compound or a combination of both in an amount say .8 to 1.0 ounce or more per square yard of fabric, the longer the fibre the more the bonding agent required for firm anchorage. Following the application of the coating of bonding agent, the pile fibres (dyed or not as desired) are deposited, as by sifting, on the upper surface of said coating and the fabric beaten on the opposite side. One or more additional applications of the pile may be provided, particularly if it is desired to apply both short into a pliable non-rigid form, as a coating to a supporting medium, embedding ends of pile fibres in said bonding agent, and thereafter reacting said bonding agent into a pliable, non-rigid form, to anchor said fibres in said bonding agent to said supporting medium.

2. The process of making a pile surfaced material which includes the steps of providing a backing, applying a naturally liquid adhesive bonding agent having the viscous gummy nondrying and stable characteristics of heat-treated rubber and capable of being thermo-set into a pliable, non-rigid form, as a coating to the back ing, embedding pile fibre ends in said bonding agent, and thereafter heat reacting said bonding agent into a pliable non-rigid resilient form, to anchor said fibres to said backing.

3. The process of making a pile fabric, which includes the steps of depositing pile fibres in a naturally liquid viscous adhesive bonding agent capable of being set to a pliable, non-rigid condition, and including as an essential constituand long pile in which case, the long pile'may ent, a liquid chloroprene polymer having 'nondrying gummy characteristics, applied as a coating to a backing, and subjecting said backing to a continued beating operation, throughout which operation said bonding agent remains in its original, naturally liquid condition.

4. The process of making a pile fabric which includes the steps of depositing pile fibres in a naturally liquid viscous adhesive bonding agent,

capable of being set to a pliable non-rigid con-.

dition, and including as an essential constituent, a chloroprene polymer having tacky nondrying characteristics at substantially normal room temperatures, applied as a coating to a backing, and subjecting said backing to a con- I tinuedbeatin'g operation, throughout which op- 6. The 'process of manufacturing a pile surfaced material which includes the steps of providing a backing, applying a naturally liquid adhesive bonding'agent having the viscous nondrying, gummy characteristics at substantially normal room temperatures of heat-treated rubber,"as a coating to the backing, embedding a portion of pile fibres in said bonding agent, and

thereafter setting up said bonding agent to a pliable, non-rigid condition, to anchor the ends of said fibres in said bonding agent to said backing.

7. A pile' fabric comprising a flexible backing and pile material anchored thereto by an adhesive consisting essentially of a naturally liquid chloroprene polymerized to a non-rigid pliable state after application of the pile material thereto. a

8. A pilefabric comprising a flexible backing and pile material anchored thereto by a thermoset bonding agent, including as an-essential constituent, a chloroprene polymer.

9. A pile fabric comprising a flexible backing and pile material anchored thereto by an adhesive including as an essential constituent, a chloroprene polymer set to a non-rigid pliable state after application of the pile material thereto.

10. A. pile surfaced material comprising a supporting medium and long pile material anchored to the supporting medium, substantially inaccordance with the process of claim 1.

11. The process of making a pile fabric which consists in depositing pile fibers in a stable and naturally liquid adhesive bonding agent including as an essential constituent, heat treated rubber having viscous, non-drying, gummy characteristics and capable of being set to a pliable non-rigid condition applied as a coating to a backing, and subjecting said backing to a continued beating operation throughout which operation said bonding agent remains in its original stable, naturally liquid and firmly adherent condition.

12. The method of makingpile fabric which comprises applying a mixture of viscous nondrying, gummy adhesive, heat treated rubber, and curing materials to a backing web to form a naturally liquid coating thereon, applying pile material to said coating and beating the backing on the opposite side from said coating to embed the fibers therein, and then vulcanizing said coating and thereby changing it from its naturally'liquid to a solid condition permanently bonding the pile material to the backing.

-l3. The process of making a long pile fabric which consists in sizing long pile fibers to produce smooth, straight, relatively stiff individual units, and thereafter embedding sized ends of said units in a liquid fiber-to-base bonding agent including as the essential constituent thereof heat-treated rubber, having viscous, non-drying, gummy characteristics, and capable of being set to a pliable, non-rigid form.

14. The steps in the process of making a pile fabric comprising sizing pile fibers with a water soluble size at substantially normal room temperatures to produce smooth, straight, relatively stiff units, adhesively anchoring ends only of said sized units to a backing, and thereafter removing said size.

15. The steps in the process of making a pile fabric comprising sizing pile fibers to produce smooth, straight, relatively stiff individual units, adhesively anchoring ends only of said sized units to a backing by embedding said sized ends in a fiber-to-base bonding agent on said backing, and thereafter removing said size from adhesive-free portions of said anchored fibers.

16. The steps in the process of making a pile fabric comprising sizing pile fibers to produce smooth, straight, relatively stiff individual units, adhesively anchoring ends only of said sized units to a backing in a fiber-to-base bonding agent on said backing, and thereafter removing said size.

1'7. A pile fabric comprising a backing and a long pile material anchored to the backing, substantially in accordance with the process of claim 16.

18. The method. of making pile fabric which comprises applyin an adhesive having as an essential constituent, heat treated rubber, mixed with curing materials, to a backing web to form a naturally liquid coating thereon, applying short pile and long pile material to said coating and beating the backing on the opposite side from said coating to embed the fibers therein, and then vulcanizing said coating and thereby changing it from its naturally liquid to a solid condition permanently bonding the pile material to the backing.

19. The method of making pile fabric which comprises applying an adhesive having as an essential constituent, heat treated rubber, mixed with curing materials, to a backing web to form a naturally liquid coating thereon, applying a long pile material and then applying a somewhat shorter pile material to said coating and beating the backing on the opposite side from said coating to embed the fibers therein, and then vulcanizing said coating and thereby changing it from its naturally liquid toa solid condition permanently bonding the pile material to the backing.

20. The method of making pile fabric which comprises applying an adhesive having as an essential constituent, heat treated rubber, mixed with curing materials, to a backing web to form a naturally liquid coating thereon, applying a small amount of short pile material and then applying long pile material to said coating and beating the backing on the opposite side -from said coating to embed the fibers of the pile material therein, and then vulcanizing said coating and thereby changing it from its naturally liq- 111d to a solid condition permanently bonding the pile material to the backing.

the opposite side from saidcoating to embed.

the fibers therein, and then vulcanizing said coating and thereby changing it from its naturally liquid to a solid condition permanently bonding the pile material to the backing.

22. A pile fabric comprising a backing and pile material anchored to the backing by a vulcanized bonding material consisting essentially of vulcanized residue of rubber, heat treated to render it viscous and adhesive.

23. A pile fabric comprising a backing and a long pile material anchored to the backing by a vulcanized bonding material consisting essentially of vulcanized residue of rubber, heat treated to render it viscous and adhesive.

24. A pile fabric comprising a backing and long and short pile material anchored to the backing by a vulcanized bonding material consisting essentially of vulcanized residue of rubber, heat treated to render it viscous and adhesive.

25. A pile fabric comprising a textile backing and a natural fur pile material anchored to the backing by a vulcanized bonding material consisting essentially of vulcanized residue of rubber, heat treated to render it viscous and adhesive.

26. A pile fabric comprising a backing including a, primary coating of rubber thereon and. a

pile material anchored to saidprimary coating '7 by a vulcanized bonding material consisting essentially of vulcanized residue of rubber, heat treated to render it viscous and adhesive.

27. A pile fabric comprising a backing and a sized pile material anchored to the backing by a vulcanized bonding material consisting essentially of vulcanized residue of rubber, heat treated to render it viscous and adhesive.

.28. The steps in the process of making a pile fabric, which consist in applying to a backing a naturally liquid, fiber-to-base bonding agent including as the essential constituent thereof, rubber, heat treated within a temperature range having a minimum temperature approximating 350 F., embedding fibers therein and thereafter solidifying said naturally liquid agent by heating.

29. The steps in the process of making a pile fabric, whichconsist in applying to a backing a stable and naturally liquid, fiber-to-base bonding agent including as the essential constituent thereof, rubber, heat treated within a temperature range having a minimum temperature approximating 350 F., embedding fibers therein and thereafter solidifying said stable and naturally liquid agent by vulcanization.

30. The method of making pile fabric which comprises applying a mi;-ture of rubber, heat treated within a temperature range having a minimum temperature approximating 350 F., and curing materials, to a backing web to form a naturally liquid coating thereon, applying pile material to said coating and heating the backing on the opposite side from said coating to embed the fibers therein, and then vulcanizing said coating and thereby changing it from its naturally liquid to a solid condition permanently bonding the pile material to the backing.

31. The process of making a pile fabric which consists in applying a bonding agent, including as an essential constituent thereof, rubber heat treated within a temperature range having a. minimum temperature approximating 350 F., and capable of being set to a pliable non-rigid form, as a coating, to a backing and then embed-' ding the ends only of pile fibers in said bonding agent.

32. A pile fabric comprising a backing and pile material anchored to the backing substantially in accordance with the process of claim 11.

33. A pile fabric comprising a backing and a long and short pile material anchored to the backing substantially in accordance with the process of claim 18.

34. The process of manufacturing a pile surfaced material which consists in applying a naturally liquid viscous gummy non-drying and stable bonding agent selected from the class consisting of heat-treated rubber and a chloroprene polymer, reactive into a pliable, non-rigid resilient form, as a coating to a supporting medium, embedding pile fibre ends in said bonding agent, subjecting said supporting medium to a continued beating operation, and thereafter reacting said bonding agent into a pliable nonrigid resilient form, to anchor said fibers to said supporting medium.

RAYMOND W. KENT.